U.S. patent number 8,385,756 [Application Number 12/871,283] was granted by the patent office on 2013-02-26 for failure diagnosis device, failure diagnosis method, image forming device, and recording medium.
This patent grant is currently assigned to Ricoh Company, Limited. The grantee listed for this patent is Mikiko Imazeki, Yasushi Nakazato, Osamu Satoh, Kohji Ue, Jun Yamane, Ryota Yamashina, Masahide Yamashita. Invention is credited to Mikiko Imazeki, Yasushi Nakazato, Osamu Satoh, Kohji Ue, Jun Yamane, Ryota Yamashina, Masahide Yamashita.
United States Patent |
8,385,756 |
Yamashina , et al. |
February 26, 2013 |
Failure diagnosis device, failure diagnosis method, image forming
device, and recording medium
Abstract
A first feature quantity computing unit that computes a first
feature quantity representing an average of a plurality of driving
loads recorded by a driving load of a fixing section recording unit
of an image forming device that records the driving load acquired
by a driving load acquiring unit that acquires the driving load, a
second feature quantity computing unit that computes a second
feature quantity representing a deviation of the plurality of the
driving loads, and a diagnosis unit that performs failure diagnosis
including estimation of a cause of a failure of the fixing section
using the first feature quantity and the second feature quantity
are used.
Inventors: |
Yamashina; Ryota (Kanagawa,
JP), Nakazato; Yasushi (Tokyo, JP), Satoh;
Osamu (Kanagawa, JP), Ue; Kohji (Kanagawa,
JP), Imazeki; Mikiko (Kanagawa, JP),
Yamashita; Masahide (Tokyo, JP), Yamane; Jun
(Kanagawa, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Yamashina; Ryota
Nakazato; Yasushi
Satoh; Osamu
Ue; Kohji
Imazeki; Mikiko
Yamashita; Masahide
Yamane; Jun |
Kanagawa
Tokyo
Kanagawa
Kanagawa
Kanagawa
Tokyo
Kanagawa |
N/A
N/A
N/A
N/A
N/A
N/A
N/A |
JP
JP
JP
JP
JP
JP
JP |
|
|
Assignee: |
Ricoh Company, Limited (Tokyo,
JP)
|
Family
ID: |
43625111 |
Appl.
No.: |
12/871,283 |
Filed: |
August 30, 2010 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20110052224 A1 |
Mar 3, 2011 |
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Foreign Application Priority Data
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Sep 1, 2009 [JP] |
|
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2009-201312 |
|
Current U.S.
Class: |
399/33;
399/36 |
Current CPC
Class: |
G03G
15/55 (20130101) |
Current International
Class: |
G03G
15/20 (20060101) |
Field of
Search: |
;399/33,36,122 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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6-208265 |
|
Jul 1994 |
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JP |
|
2005-309077 |
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Nov 2005 |
|
JP |
|
2008-102474 |
|
May 2008 |
|
JP |
|
Other References
US. Appl. No. 12/818,564, filed Jun. 18, 2010, Kohji Ue et al.
cited by applicant .
U.S. Appl. No. 12/822,586, filed Jun. 24, 2010, Mikiko Imazeki et
al. cited by applicant.
|
Primary Examiner: Ngo; Hoang
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier
& Neustadt, L.L.P.
Claims
What is claimed is:
1. A failure diagnosis device for a failure of a fixing section of
an image forming device, comprising: a first feature quantity
computing unit that computes a first feature quantity representing
an average of a plurality of driving loads of the fixing section
recorded by a driving load recording unit that records the driving
load acquired by a driving load acquiring unit that acquires the
driving load; a second feature quantity computing unit that
computes a second feature quantity representing a deviation of the
plurality of the driving loads recorded by the driving load
recording unit; a diagnosis unit that performs failure diagnosis
including estimation of a cause of the failure of the fixing
section using at least the first feature quantity computed by the
first feature quantity computing unit and the second feature
quantity computed by the second feature quantity computing unit;
and a third feature quantity computing unit that computes a third
feature quantity representing a maximum value among the plurality
of the driving loads recorded by the driving load recording unit,
wherein the diagnosis unit performs failure diagnosis using at
least the first feature quantity computed by the first feature
quantity computing unit, the second feature quantity computed by
the second feature quantity computing unit, and the third feature
quantity computed by the third feature quantity computing unit.
2. A failure diagnosis device for a failure of a fixing section of
an image forming device, comprising: a first feature quantity
computing unit that computes a first feature quantity representing
an average of a plurality of driving loads of the fixing section
recorded by a driving load recording unit that records the driving
load acquired by a driving load acquiring unit that acquires the
driving load; a second feature quantity computing unit that
computes a second feature quantity representing a deviation of the
plurality of the driving loads recorded by the driving load
recording unit; and a diagnosis unit that performs failure
diagnosis including estimation of a cause of the failure of the
fixing section using at least the first feature quantity computed
by the first feature quantity computing unit and the second feature
quantity computed by the second feature quantity computing unit,
wherein the diagnosis unit includes stamp weak discriminators that
are created using a boosting method and computes a preliminary
diagnosis result of the failure.
3. The failure diagnosis device according to claim 2, wherein the
diagnosis unit includes a weighted majority vote computing unit
that diagnoses the failure by performing a weighted majority vote
using the diagnosis result computed by the stamp weak
discriminators.
4. The failure diagnosis device according to claim 1, wherein the
diagnosis unit estimates a plurality of causes of the failure of
the fixing section and, when diagnosing the failure due to one of
the causes, performs an output for informing the failure and the
one of the causes.
5. A failure diagnosis device for a failure of a fixing section of
an image forming device, comprising: a first feature quantity
computing unit that computes a first feature quantity representing
an average of a plurality of driving loads of the fixing section
recorded by a driving load recording unit that records the driving
load acquired by a driving load acquiring unit that acquires the
driving load; a second feature quantity computing unit that
computes a second feature quantity representing a deviation of the
plurality of the driving loads recorded by the driving load
recording unit; and a diagnosis unit that performs failure
diagnosis including estimation of a cause of the failure of the
fixing section using at least the first feature quantity computed
by the first feature quantity computing unit and the second feature
quantity computed by the second feature quantity computing unit,
wherein the failure diagnosed by the diagnosis unit relates to poor
feeding of a releasing agent to a fixing member that is disposed in
the fixing section and abuts on a recording medium.
6. The failure diagnosis device according to claim 5, wherein the
cause of the failure of the fixing section estimated by the
diagnosis unit includes a cause related to deterioration of a
supply member that supplies the releasing agent to the fixing
member.
7. The failure diagnosis device according to claim 5, wherein the
cause of the failure of the fixing section estimated by the
diagnosis unit includes a cause related to deterioration of a
filtration member that filters the releasing agent supplied to the
fixing member.
8. The failure diagnosis device according to claim 1, wherein the
driving load acquiring unit acquires the driving load based on a
driving current of the fixing section.
9. An image forming device, comprising: the driving load acquiring
unit, wherein the failure is diagnosed by the failure diagnosis
device recited in claim 1.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority to and incorporates by
reference the entire contents of Japanese Patent Application No.
2009-201312 filed in Japan on Sep. 1, 2009.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a failure diagnosis device and a
failure diagnosis method for a failure of an image forming device
such as a copy machine, a printer, and a facsimile, particularly, a
failure of a fixing section, an image forming device in which the
failure is diagnosed by the failure diagnosis device or the failure
diagnosis method, and a computer program product comprising a
computer-usable medium having computer-readable program codes
embodied in the medium for executing the failure diagnosis
method.
2. Description of the Related Art
An image forming device such as a copy machine, a printer, and a
facsimile includes a number of units or components. When
abnormality occurs in the image forming device due to a failure or
the end of life of the unit, etc., it is necessary to perform
repair or maintenance such as replacement. Some or all functions of
the image forming device need to be stopped while the repair is
performed. In performing the repair, it may take a long time to
find out a cause of abnormality, and thus there is a problem in
that a user is inconvenienced because it is impossible to use the
image forming device during that time in addition to a net time of
repair or the like. This problem also occurs when the maintenance
on a portion in which abnormality is likely to occur is performed
before abnormality occurs. In order to solve the problem, it is
required to diagnose where abnormality of the image forming device
occurs or is likely to occur to perform the maintenance, etc.,
thereby reducing downtime.
In this regard, a technique for estimating a failure portion (for
example, see Japanese Patent Application Laid-open No. 06-208265),
a technique for extracting a candidate of a failure portion or a
portion that is likely to cause a failure (for example, see
Japanese Patent Application Laid-open No. 2005-309077), and a
technique for determining whether or not a device is in an abnormal
state or anticipating an occurrence of a failure in a device (for
example, see Japanese Patent Application Laid-open No. 2008-102474)
have been suggested.
Meanwhile, as one of constitutions disposed in the image forming
device, a fixing section has a larger number of components in
general and is relatively higher in cost than other constitutions.
Since the fixing section has a larger number of components, various
causes may be considered as a cause of its trouble or its failure.
Therefore, the same problem as the problem described above, for
example, a problem in that a time taken for maintenance tends to
become longer and unnecessary maintenance may be performed for a
portion different from a cause is exactly applied to the fixing
section. Consequently, similarly, in order to solve the problem in
the fixing section, it is important to diagnose where abnormality
of the fixing section occurs or is likely to occur to perform the
maintenance, thereby reducing downtime.
In this regard, the applicant previously suggested a failure
diagnosis device that performs failure diagnosis of a fixing
section disposed in an image forming device including estimation of
a cause of trouble related to a paper transport time in the fixing
section in Japanese Patent Application No. 2009-163382.
However, since trouble in the fixing section is not caused only in
connection with the paper transport time, it is required to
additionally suggest a technique for being capable of dealing with
other causes of trouble.
SUMMARY OF THE INVENTION
It is an object of the invention to at least partially solve the
problems in the conventional technology.
According to an aspect of the present invention there is provided a
failure diagnosis device for a failure of a fixing section of an
image forming device. The failure diagnosis device includes: a
first feature quantity computing unit that computes a first feature
quantity representing an average of a plurality of driving loads of
the fixing section recorded by a driving load recording unit that
records the driving load acquired by a driving load acquiring unit
that acquires the driving load; a second feature quantity computing
unit that computes a second feature quantity representing a
deviation of the plurality of the driving loads recorded by the
driving load recording unit; and a diagnosis unit that performs
failure diagnosis including estimation of a cause of the failure of
the fixing section using at least the first feature quantity
computed by the first feature quantity computing unit and the
second feature quantity computed by the second feature quantity
computing unit. According to another aspect of the present
invention there is provided a failure diagnosis method for a
failure of a fixing section of an image forming device. The failure
diagnosis method includes: computing, by a first feature quantity
computing unit, a first feature quantity representing an average of
a plurality of driving loads of the fixing section recorded by a
driving load recording unit that records the driving load acquired
by a driving load acquiring unit that acquires the driving load;
computing, by a second feature quantity computing unit, a second
feature quantity representing a deviation of the plurality of the
driving loads recorded by the driving load recording unit; and
performing, by a diagnosis unit, failure diagnosis including
estimation of a cause of the failure of the fixing section using at
least the first feature quantity computed by the first feature
quantity computing unit and the second feature quantity computed by
the second feature quantity computing unit. The above and other
objects, features, advantages and technical and industrial
significance of this invention will be better understood by reading
the following detailed description of presently preferred
embodiments of the invention, when considered in connection with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a control block diagram illustrating an overview of a
failure diagnosis device according to the invention;
FIG. 2 is a schematic front view illustrating an image forming
device illustrated in FIG. 1;
FIG. 3 is a control block diagram illustrating a configuration of a
fixing section and a failure diagnosis device disposed in the image
forming device illustrated in FIG. 2;
FIG. 4 is a correlation diagram illustrating a correlation between
a current value of a fixing driving motor as a driving load of a
fixing section and a timing at which a paper passes the fixing
section;
FIG. 5 is a correlation diagram illustrating effectiveness of first
to third feature quantities in failure diagnosis of a fixing
section;
FIG. 6 is a correlation diagram illustrating a result of performing
failure diagnosis of a fixing section using first to third feature
quantities used to construct a diagnosis unit through the diagnosis
unit constructed using the feature quantities; and
FIG. 7 is a control block diagram illustrating part of an image
forming device including a failure diagnosis device according to
the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 schematically illustrates a failure diagnosis system
according to the invention.
The failure diagnosis system 1 includes a failure diagnosis device
110 to which the invention is applied, a plurality of image forming
devices 100 that are failure diagnosis targets of the failure
diagnosis device 110, a plurality of Local Area Networks (LANs)
120, as a first network, that each connect the image forming
devices 100 within a predetermined area among the plurality of
image forming devices 100 with each other, and the Internet 130, as
a second network, that connects the plurality of LANs 120 with the
failure diagnosis device 110.
The failure diagnosis system 1 further includes a personal computer
(PC) 140 that is a terminal as an operation terminal operated by an
operator such as an administrator who performs operation and
maintenance management on the failure diagnosis device 110
maintenance management on the image forming devices 100, etc., and
a LAN 150 that is a third network that connects the failure
diagnosis device 110 with the PC 140.
The failure diagnosis device 110 is configured as a server for the
PC 140. The details of the failure diagnosis device 110 will be
described later.
The LAN 120 includes a HUB section 121 that is connected not only
with the image forming device 100 but also with the Internet 130.
The LAN 120, the HUB section 121, and the Internet 130 are not
indispensable and may be appropriately combined. For example, the
image forming devices 100 may be connected directly with the
Internet 130 or with the failure diagnosis device 110, or the LAN
120 may be connected directly with the failure diagnosis device
110. The LAN 120 and the LAN 150 may be the same one.
FIG. 2 illustrates an overview of the image forming device 100. The
image forming device 100 is a complex machine of a copy machine, a
printer, and a facsimile and is configured to perform full-color
image forming. When used as a printer and a facsimile, the image
forming device 100 performs an image forming process based on an
image signal corresponding to image information received from the
outside via the LAN 120, a telephone line, etc.
The image forming device 100 can form an image on a sheet-like
recording medium, which may be a transferred material or a
recording paper, including a thick paper such as an OHP sheet, a
card, and a postcard, and an envelop as well as a regular paper
generally used for copying purposes or the like.
The image forming device 100 is a color image forming device of a
tandem system or a tandem type that employs a tandem structure in
which cylindrical drum-shaped photosensitive elements 20BK, 20Y,
20M, and 20C, which are latent image carriers as image carriers
that can form images respectively corresponding to colors
decomposed into colors of yellow, magenta, cyan, and black, are
disposed in tandem.
The photosensitive elements 20BK, 20Y, 20M, and 20C have the same
diameter and are disposed in tandem at an equal interval on an
outer circumferential surface side, i.e., an image formed surface
side of a transfer belt 11 as an intermediate transfer belt
corresponding to an intermediate transfer body that is an endless
belt disposed at substantially a center inside a main body 99 of
the image forming device 100. The transfer belt 11 is movable in a
direction of an arrow A1 while confronting the photosensitive
elements 20BK, 20Y, 20M, and 20C.
The photosensitive elements 20BK, 20Y, 20M, and 20C are arranged in
tandem in this order from an upstream side of the A1 direction. The
photosensitive elements 20BK, 20Y, 20M, and 20C are disposed in
image stations 60BK, 60Y, 60M, and 60C that are image forming unit
corresponding to image forming sections as sections for forming
images of black, yellow, magenta, and cyan, respectively.
Visible images, i.e., toner images formed on the photosensitive
elements 20BK, 20Y, 20M, and 20C are transferred onto the transfer
belt 11 that moves in the arrow A1 direction in a superimposed
manner, and then are collectively transferred onto a transfer sheet
S corresponding to a transferred medium that is a recording
medium.
The superimposed transfer on the transfer belt 11 is performed at
transfer positions where the transfer belt 11 faces the
photosensitive elements 20BK, 20Y, 20M, and 20C, by applying a
voltage through primary transfer rollers 12BK, 12Y, 12M, and 12C as
transfer chargers disposed at positions facing the photosensitive
elements 20BK, 20Y, 20M, and 20C with the transfer belt 11
interposed therebetween at timings shifted from an upstream side to
a downstream side in the A1 direction so that the toner images
formed on the photosensitive elements 20BK, 20Y, 20M, and 20C is
transferred onto the same position of the transfer belt 11 in a
superimposed manner while the transfer belt 11 moves in the A1
direction.
The image forming device 100 includes the main body 99 that
occupies a central position in an up-down direction, a reading
device 21 as a scanner that is positioned above the main body 99
and reads an original document, an automatic document feeder 22
called an ADF that is positioned above the reading device 21,
stacks the original document thereon, and feeds the stacked
original document to the reading device 21, and a sheet feed device
23 as a paper feed table that is positioned below the main body 99
and stacks the transfer sheet S to be transported toward between
the photosensitive elements 20BK, 20Y, 20M, and 20C and the
intermediate transfer belt 11 thereon.
The image forming device 100 further includes four image stations
60BK, 60Y, 60M, and 60C, a transfer belt unit 10 that is an
intermediate transfer device as an intermediate transfer unit that
is opposedly disposed below the photosensitive elements 20BK, 20Y,
20M, and 20C and includes the transfer belt 11, and a secondary
transfer device 47 that is a secondary transfer unit as a transfer
unit that is opposedly disposed below the transfer belt unit 10 and
transfers the toner image on the transfer belt 11 onto the transfer
sheet S.
The image forming device 100 further includes a cleaning device 32
that is an intermediate transfer belt cleaning unit as an
intermediate transfer belt cleaning device that is disposed to face
the transfer belt 11 between the secondary transfer device 47 and
the image station 60BK in the direction A1 and cleans the surface
of the transfer belt 11.
The image forming device 100 further includes an optical scanning
device 8 corresponding to a latent image forming unit as an optical
writing device that is a writing unit that is opposedly disposed
above the image stations 60BK, 60Y, 60M, and 60C, a waste toner
storing section 34 for the intermediate transfer body that is
disposed to face the secondary transfer device 47 below the
secondary transfer device 47, and a toner transport path (not
shown) that connects the cleaning device 32 with the waste toner
storing section 34 for the intermediate transfer body.
The image forming device 100 further includes a resist roller pair
13 that delivers the transfer sheet S transported from the sheet
feed device 23 toward the secondary transfer section between the
transfer belt 11 and the secondary transfer device 47 at a
predetermined timing matched to the timings of forming the toner
image by the image stations 60BK, 60Y, 60M, and 60C, and a sensor
(not shown) that detects the front end of the transfer sheet S
arrived at the resist roller pair 13.
The image forming device 100 further includes a fixing device 6
corresponding to a fixing section that is a fixing unit of a belt
fixing system that, after a toner image is transferred, fixes the
same toner image onto the transfer sheet S transported in the arrow
C1 direction, a discharging roller 7 that discharges the transfer
sheet S having passed through the fixing device 6 to the outside of
the main body 99, and a side plate 89 that is openably or closably
disposed at a position facing the fixing device 6.
The image forming device 100 further includes a paper discharge
tray 17 as a paper discharge section that is disposed above the
main body 99 and stacks the transfer sheet S discharged to the
outside of the main body 99 by the discharging roller 7 thereon,
and a toner bottle (not shown) in which toners of colors of yellow,
magenta, cyan, and black are filled.
The image forming device 100 further includes a control section 36
as a control unit that controls an overall operation of the image
forming device 100, a communication section 37 as a communication
unit that is connected with a LAN 120, controlled by the control
section 36, and performs communication with the failure diagnosis
device 110, and an operation panel 40 through which an operator
such as a user performs an operation of the image forming device
100 as illustrated in FIG. 3.
As illustrated in FIG. 2, the image forming device 100 is an image
forming device of an in-body discharge type in which the paper
discharge tray 17 is disposed above the main body 99 and below the
reading device 21. The transfer sheet S stacked on the paper
discharge tray 17 is taken out to a downstream side of the D1
direction corresponding to the left in FIG. 2.
The transfer belt unit 10 includes primary transfer rollers 12BK,
12Y, 12M, and 12C, a tension roller 72 around which the
intermediate transfer belt 11 is wound, a cleaning counter roller
73 that is disposed to face the cleaning device 32 with the
intermediate transfer belt 11 interposed therebetween and also
functions as the driving roller, a transfer entrance roller 74 as a
secondary transfer counter roller that is not only a driven roller
facing the secondary transfer device 47 with the intermediate
transfer belt 11 interposed therebetween but also a stretching
roller, a spring 28 that urges the tension roller 72 in a direction
away from the cleaning counter roller 73, and a pair of
intermediate transfer section side plates (not shown) that are
disposed to rotatably support both sides of each of the rollers
over which the transfer belt 11 is stretched, that is, the tension
roller 72, the cleaning counter roller 73, and the transfer
entrance roller 74 and interpose the intermediate transfer belt 11
therebetween.
The secondary transfer device 47 includes a secondary transfer
roller 5 that is a secondary transfer counter roller as a transfer
member that rotates in the same direction as the transfer belt 11
at a position abutting on the transfer belt 11 and a high voltage
source (not shown) that is connected with the secondary transfer
roller 5 and applies a secondary transfer bias to the transfer belt
11 to transfer the toner image on the transfer belt 11 onto the
transfer sheet S. A bias value applied by the high voltage source
is controlled by the control section 36.
The secondary transfer roller 5 faces the transfer entrance roller
74 with the transfer belt 11 interposed therebetween and forms a
secondary transfer section between itself and the intermediate
transfer belt 11. The secondary transfer roller 5 is constituted by
coating an elastic body made of urethane whose resistance is
adjusted by a conductive material on a cored bar made of metal such
as steel use stainless (SUS).
The cleaning device 32 includes an intermediate transfer cleaning
blade 35 as a cleaning blade that abuts on the transfer belt 11 at
a position facing the cleaning counter roller 73. The cleaning
device 32 cleans the transfer belt 11 by scraping undesired
substances such as toners or paper powder which remain on the
transfer belt 11 after transfer, through the intermediate transfer
cleaning blade 35.
The intermediate transfer cleaning blade 35 abuts on the transfer
belt 11 in a counter direction. Undesired substances such as
toners, which remain after transfer, scraped by the intermediate
transfer cleaning blade 35 are passed through the toner transport
path and stored in the waste toner storing section 34 for the
intermediate transfer body. At least one of a portion of the
transfer belt 11 corresponding to a cleaning nip portion that abuts
on the intermediate transfer cleaning blade 35 and an edge portion
of the intermediate transfer cleaning blade 35 is coated with a
liniment such as a lubricant agent, a toner, and a zinc stearate
when mounted. Therefore, the intermediate transfer cleaning blade
35 is prevented from being rolled up in the cleaning nip portion
and forms a dam layer in the cleaning nip portion so that a
cleaning performance is improved.
The optical scanning device 8 is a laser beam scanner that uses a
laser diode as a light source. The optical scanning device 8 scans
and exposes scanned surfaces composed of surfaces of the
photosensitive elements 20BK, 20Y, 20M, and 20C and emits beams
LBK, LY, LM, and LC that are laser light as laser beam based on an
image signal to form an electrostatic latent image. The optical
scanning device 8 may use a light emitting diode (LED) as a light
source.
The optical scanning device 8 is detachably attached to the main
body 99 and is configured so that process cartridges, which will be
described later, respectively disposed in the image stations 60BK,
60Y, 60M, and 60C can be independently taken out of the main body
99 when the optical scanning device 8 is detached.
The sheet feed device 23 includes a paper feed tray 15 on which the
transfer sheet S is stacked and a paper feeding roller 16 as a
paper feed transport roller that feeds the transfer sheet S stacked
on the paper feed tray 15. The paper feed tray 15 is configured to
be able to stack transfer sheets S of multiple sizes.
The reading device 21 is positioned above the main body 99 and is
combined with the main body 99 to be turnable by a shaft 24
disposed at an end portion of the image forming device 100 at the
upstream side of the D1 direction, in other words, at a back side
of the image forming device 100 to be openable or closable relative
to the main body 99.
The reading device 21 includes, at a D1 direction downstream side
end thereof, a grip section 25 that is gripped to open the reading
device 21 from the main body 99. The reading device 21 is turnable
on the shaft 24 and so is opened from the main body 99 by gripping
and upward turning the grip section 25. An opening angle of the
reading device 21 to the main body 99 is about 90.degree., and thus
it is easy to perform an operation of accessing the inside of the
main body 99 and closing the reading device 21.
The reading device 21 includes a contact glass 21a on which the
original document is placed, a first traveling body 21b that
includes a light source (not shown) for irradiating light to the
original document placed on the contact glass 21a and a first
reflector (not shown) for reflecting light that is irradiated from
the light source and reflected by the original document and travels
in a left-right direction in FIG. 2, a second traveling body 21c
that includes a second reflector (not shown) for reflecting light
reflected by the reflector of the first traveling body 21b, an
imaging lens 21d that focuses light from the second traveling body
21c, and a reading sensor 21e that receives light having passed
through the imaging lens 21d and reads a content of the original
document.
The automatic document feeder 22 is positioned above the reading
device 21 and is combined with the reading device 21 to be turnable
by a shaft 26 disposed at an end portion of the image forming
device 100 at the D1 direction upstream side to be openable or
closable relative to the reading device 21.
The automatic document feeder 22 includes a grip section 27 that is
gripped to open the automatic document feeder 22 from the reading
device 21 at the D1 direction downstream side end. The automatic
document feeder 22 is turnable on the shaft 26 and so is opened
from the reading device 21 by gripping and upward turning the grip
section 27, exposing the contact glass 21a.
The automatic document feeder 22 includes a platen 22a on which the
original document is placed and a driving section including a motor
(not shown) that feeds the original document placed on the platen
22a. In order to perform copying through the image forming device
100, the original document is set on the platen 22a of the
automatic document feeder 22, or the automatic document feeder 22
is turned upward, the original document is manually placed on the
contact glass 21a, and then the automatic document feeder 22 is
closed to press the original document against the contact glass
21a. An opening angle of the automatic document feeder 22 to the
reading device 21 is about 90.degree., and thus it is easy to place
the original document on the contact glass 21a and perform a
maintenance work on the contact glass 21a.
As illustrated in FIG. 3, the fixing device 6 includes a heating
roller heater 61 as a heat source, a heating roller 62 of a roller
shape inside which the heating roller heater 61 is disposed, a
fixing belt 64 as a fixing member that is wound around the heating
roller 62, a fixing roller 65 of a roller shape that is rotatable
on a shaft 65a and around which, and around the heating roller 62,
the fixing belt 64 is wound, and a pressing roller 63 as a pressing
member of a roller shape that is disposed at a position facing the
fixing roller 65 with the fixing belt 64 interposed therebetween
and comes in press contact with the fixing belt 64 between itself
and the fixing roller 65 to form a fixing nip 80 that is a press
contact section.
The fixing device 6 includes a first thermistor 76 and a first
thermostat 77 that detect a temperature of a portion of the fixing
belt 64 wound around the heating roller 62, and a second thermistor
78 and a second thermostat 79 that detect a temperature of the
pressing roller 63 near an upstream side of the fixing nip 80 in
the rotation direction of the pressing roller 63.
The fixing device 6 further includes an entrance guide plate 81
that is disposed at an upstream side of the fixing nip 80 in a C1
direction and guides the transfer sheet S to the fixing nip 80 and
an exit guide plate 82 that is disposed at a downstream side of the
fixing nip 80 in the C1 direction and guides and discharges the
transfer sheet S having passed through the fixing nip 80 to the
outside of the fixing device 6.
The fixing device 6 further includes a fixing entrance sensor 83
that detects the front end of the transfer sheet S that enters the
inside of the fixing device 6 and is guided by the entrance guide
plate 81 and a fixing exit sensor 84 that detects the front end of
the transfer sheet S that has been passed through the fixing nip 80
and is guided by the exit guide plate 82 to be discharged to the
outside of the fixing device 6.
The fixing device 6 further includes a driving gear 75, which is a
fixing driving gear as an image forming device main body side
member disposed at the main body 99 side, and that is disposed
integrally with the shaft 65a and rotatively drives the fixing
roller 65, the fixing belt 64, the heating roller 62, and the
pressing roller 63, and a motor 86 that is a driving source as a
fixing driving source that includes an output gear 86a meshed with
the driving gear 75 and rotatively drives the fixing roller 65, the
fixing belt 64, the heating roller 62, and the pressing roller 63
and that is also a fixing driving motor as an image forming device
main body side member disposed at the main body 99 side.
The fixing device 6 further includes a releasing agent supply unit
90 that is a releasing agent coating unit that coats and supplies
the fixing belt 64 with a releasing agent for improving
releasability between the fixing belt 64 and the transfer sheet S,
and a fixing case 85 that supports components excluding the driving
gear 75 and the motor 86 among the above-described components
disposed in the fixing device 6 in a surrounding manner.
The components excluding the driving gear 75 and the motor 86 among
the above-described components disposed in the fixing device 6 form
a fixing unit that is detachably attached to the main body 99. When
the side plate 89 is opened, the fixing device 6 is exposed to the
outside of the main body 99, so that the fixing unit can be taken
out of the main body 99. Such unitization makes it possible to
handle the fixing device 6 as a replacement component, and thus it
is easy to access it, for the purpose of repair, etc., in a state
taken out of the main body 99. Therefore, since maintenancebility
is significantly improved, it is very desirable. When the fixing
unit is taken out of the main body 99, the driving gear 75 and the
motor 86 among the above-described components disposed in the
fixing device 6 are left on the main body 99 side, and the driving
gear 75 is exposed toward the outside of the main body 99. This
makes it easy to access the driving gear 75 and the motor 86 from
the outside of the main body 99, and thus repair, replacement or
the like can be easily performed.
Both the fixing entrance sensor 83 and the fixing exit sensor 84
are configured with a reflective type photointerrupter and detect
the front end of the transfer sheet S by detecting the reflected
light when the transfer sheet S is passing through. Both the fixing
entrance sensor 83 and the fixing exit sensor 84 input signals
representing that they are detecting the transfer sheet S to the
control section 36.
The first thermistor 76, the first thermostat 77, the second
thermistor 78, and the second thermostat 79 are used to enable the
fixing nip 80 to keep a temperature suitable for fixing. The
temperatures detected by them are appropriately used in driving
control of the heating roller heater 61.
The heating roller 62 is heated by the heating roller heater 61,
and the fixing belt 64 is heated by heat of the heating roller 62.
The fixing belt 64 and the pressing roller 63 are rotatively driven
by the fixing roller 65 that is rotatively driven by the motor
86.
The pressing roller 63 has a shaft 63a which becomes a rotation
center thereof. The shaft 63a is movably supported to the fixing
case 85 so that a circumferential surface of the pressing roller 63
can contact with or be separated from the fixing belt 64. The
pressing roller 63 comes in press contact with the fixing belt 64
and the fixing roller 65 to form the fixing nip 80.
In order to improve an image quality, a surface of the fixing belt
64 at the pressing roller 63 side, that is, at a side that comes in
contact with a surface or an image surface of the transfer sheet S,
has a mirror surface, which enables the fixing belt 64 to easily
come in close contact with the transfer sheet S. The fixing belt 64
has the mirror surface and thus easily comes in close contact with
the transfer sheet S, but it tends to decrease separation of the
transfer sheet S.
The releasing agent supply unit 90 coats and supplies the fixing
belt with the releasing agent for improving releasability between
the fixing belt 64 and the transfer sheet S in order to improve
separation between the surface of the fixing belt 64 and the
transfer sheet S. The releasing agent is not limited to but may
include a liquid releasing agent such as silicon oil or a powder
releasing agent such as paraffin. In the present embodiment,
silicon oil that is high in thermal resistance and is widely used
as a releasing agent for fixing is used as the releasing agent.
Hereinafter, the releasing agent is referred to simply as
"oil".
The releasing agent supply unit 90 includes an oil coating roller
91 that is a first releasing agent coating member corresponding to
a first releasing agent coating roller that abuts on the fixing
belt 64 at a position facing the heating roller 62 and rotates
together with the fixing belt 64 to coat and supply the fixing belt
64 with oil, and an oil supply roller 92 that is a second releasing
agent supply member corresponding to a second releasing agent
supply roller that abuts on the oil coating roller 91 at a position
of a side opposite to the heating roller 62 and rotates together
with the oil coating roller 91 to supply the oil coating roller 91
with oil.
The releasing agent supply unit 90 further includes a coating felt
93 that is an oil coating felt as a supply member corresponding to
a releasing agent supply member as a releasing agent coating member
that abuts on the oil supply roller 92 at a position opposite to
the oil coating roller 91 and comes in slide contact with the oil
supply roller 92 to spread and supply oil to the oil supply roller
92 and is detachably attached to the releasing agent supply unit 90
main body, and an oil pan 94 that is disposed above the coating
felt 93 and supplies the coating felt 93 with oil by dropping
oil.
The releasing agent supply unit 90 further includes a tank 95
corresponding to an oil tank that is an oil reservoir as a
releasing agent reservoir in which oil is stored, an oil tube 96
that is a first oil tube as a first releasing agent supply tube
that allows oil to pass through the inside thereof and supplies the
oil pan 94 with oil stored in the tank 95, a pump 97 that pumps oil
toward the oil pan 94 by sucking oil stored in the tank into the
oil tube 96 and passing oil through the oil tube 96, and a driving
power source (not shown) as a releasing agent supply driving source
that applies a driving voltage to the pump 97.
The releasing agent supply unit 90 further includes an oil plate 98
as a releasing agent receiver that receives and collects a surplus
of oil supplied to the fixing belt 64 or a surplus of oil supplied
to be transferred from the fixing belt 64 to the pressing roller
63, an oil tube 87 (partially not shown) that is a second oil tube
as a second releasing agent supply tube that passes oil collected
in the oil plate 98 through the inside thereof to be returned to
the tank 95, and an oil filter 88 corresponding to a releasing
agent filter that is a releasing agent filtration member that is
detachably attached to a middle portion of the oil tube 87, filters
and removes impurities such as paper powder or toners contained in
oil passing through the inside of the oil tube 87 to clean oil, and
returns clean oil to the tank 95.
In the releasing agent supply unit 90 having such a configuration,
when the pump 97 is driven by the driving power source, the driven
pump 97 supplies oil in the tank 95 to the oil pan 94 via the oil
tube 96, and oil supplied to the oil pan 94 is coated on the fixing
belt 64 through the coating felt 93, the oil supply roller 92, and
the oil coating roller 91. Part of oil coated on the fixing belt 64
is attached to the transfer sheet S and expended when the transfer
sheet S passes through the fixing nip 80, but a surplus is
collected in the oil plate 98 directly from the fixing belt 64 or
from the pressing roller 63 after attached to the pressing roller
63 abutting on the fixing belt 64, passes through the oil tube 87,
then cleaned by the oil filter 88 in the middle, and returned to
the tank 95. In this way, the releasing agent supply unit 90
repetitively circulates oil to be reused and thus is excellent in
economic and environmental efficiencies. The tank 95 stores oil of
a sufficient amount anticipated considering both that oil is
circulated and used and that oil is expended.
The transfer sheet S on which the toner image is supported passes
through the fixing device 6 with being tucked in the fixing nip 80
so that the surface of the transfer sheet S can contact the fixing
belt 64. As a result, the supported toner image is fixed onto the
surface of the transfer sheet S by influence of heat of the fixing
belt 64 heated by the heating roller heater 61 via the heating
roller 62 and pressure between the fixing belt 64 and the pressing
roller 63.
The fixing device 6 changes a process speed, that is, a rotation
speed of the heating roller 62, the pressing roller 63, the fixing
belt 64, and the fixing roller 65 at the time of fixing by changing
the driving speed of the motor 86 according to a kind of the
transfer sheet S. Specially, according to the paper thickness, the
ticker the paper thickness is, the slower the process speed is. The
thicker the thickness of the transfer sheet S is, the slower the
transfer sheet S passes through the fixing nip 80, thereby securing
fixability of the toner image. Driving control of the motor 86
including changing the driving speed of the motor 86 is performed
by the control section 36.
The other functions of the fixing device 6 will be described
later.
Even though not shown, the control section 36 includes a central
processing section (CPU) and, as a memory, a read only memory (ROM)
as a first memory unit that stores an operation program of the
image forming device 100 and a variety of data necessary for an
operation of the operation program and a random access memory (RAM)
as a second memory unit that stores data necessary for an operation
of the image forming device 100.
The control section 36 computes and acquires a time, which is taken
from a point in time when the front end of the transfer sheet S
starts to be detected by the fixing entrance sensor 83 to a point
in time when the front end of the transfer sheet S starts to be
detected by the fixing exit sensor 84, based on a difference
between a signal reception start time from the fixing entrance
sensor 83 and a signal reception start time from the fixing exit
sensor 84 through the CPU as a paper transport time in the fixing
device 6 and stores the paper transport time in the RAM. In this
regard, the control section 36 functions as a paper transport time
computing unit, a paper transport time acquiring unit, and a paper
transport time recording unit as a first paper transport time
recording unit. Further, the paper transport time computing unit or
the paper transport time acquiring unit may include the fixing
entrance sensor 83 or the fixing exit sensor 84 in addition to the
control section 36.
In a state in which an integration value of a number of sheets on
which an image is formed is equal to or more than a set value, at a
time immediately after an operation voltage of the image forming
device 100 is applied or when an image forming operation is
finished, the control section 36 drives a communication section 37
and requests the failure diagnosis device 110 to perform
communication for transmitting the paper transport time stored in
the control section 36 as the paper transport time recording unit
while identifying the corresponding image forming device 100 to the
failure diagnosis device 110.
The other operations and functions of the control section 36 will
be described later.
The operation panel 40 includes a ten key 41 for designating an
image forming number, a print start key 42 for instructing a start
of image forming, and a liquid crystal display (LCD) device 43 as a
display unit for displaying a state of the image forming device 100
to a user.
In connection with the image stations 60BK, 60Y, 60M, and 60C, a
configuration of the image station 60BK having the photosensitive
element 20BK will be representatively described with reference to
FIG. 2. Since the configurations of the other image stations are
substantially the same, for convenience, it is assumed in the
following explanation that symbols corresponding to symbols
attached to the configuration of the image station 60BK are
attached to the configurations of the other image stations, and
detailed description thereof will be appropriately omitted. BK, Y,
M, C added behind the symbols represent configurations for forming
images of black, yellow, magenta, and cyan, respectively.
The image station 60BK having the photosensitive element 20BK
includes a primary transfer roller 12BK, a cleaning device 70BK as
a cleaning unit for cleaning the photosensitive element 20BK, a
charging device 30BK corresponding to a charging charger as a
charging device that is a charging unit for charging the
photosensitive element 20BK to a high voltage, and a developing
device 50BK that is a developer as a developing unit for developing
the photosensitive element 20BK, which are disposed around the
photosensitive element 20BK along a rotation direction B1 that is a
clockwise direction in FIG. 2.
The photosensitive element 20BK, the cleaning device 70BK, the
charging device 30BK, and the developing device 50BK are integrated
to constitute the process cartridge. The process cartridge is
detachably attached to the main body 99. Constituting the
components as one process cartridge is very desirable because the
components can be handled as a single unitized replacement
component, thereby significantly improving maintenancebility.
The photosensitive element 20BK is rotatively driven at a
peripheral speed of 120 mm/s.
The charging device 30BK includes a brush roller (details are not
shown) and a high voltage source (not shown) that applies a bias to
the brush roller. The brush roller comes in press contact with the
surface of the photosensitive element 20BK and is drivenly rotated
by the photosensitive element 20BK. The high voltage source applies
a bias in which an alternating current (AC) is superimposed to a
direct current (DC) but it may alternatively apply a DC bias. The
surface of the photosensitive element 20BK is uniformly charged to
-500 V by the charging device 30BK.
The developing device 50BK includes a developing roller 51BK
disposed at a position facing the photosensitive element 20BK, a
developing roller driving motor (not shown) as a driving source
that rotatively drives the developing roller 51BK, and a high
voltage source (not shown) that applies a developing bias to the
developing roller 51BK.
The developing roller 51BK has a diameter of .phi.12 mm and is
rotatively driven at a linear speed of 160 mm/s by the driving
roller driving motor. Driving of the developing roller driving
motor is controlled by the control section 36. The developing
device 50BK performs one component contact development and uses, as
a developer, a toner having a minus polarity as a normal charging
characteristic. The developing device 50BK stores the toner of 180
g in a new state, in other words, initially.
In the image forming device having the above-described
configuration, when performing full-color image forming and the
print start key 42 in the operation panel 40 is held down, the
photosensitive element 20BK rotates in the B1 direction. With this
rotation, the surface of the photosensitive element 20BK is
uniformly charged by the charging device 30BK and a beam LBK is
exposure-scanned by the optical scanning device 8 so that an
electrostatic latent image is formed based on image information
corresponding to black. The electrostatic latent image is formed by
scanning the beam LBK in a main scanning direction that is a
vertical direction to the paper plane and performing scanning in a
sub scanning direction that is a circumferential direction of the
photosensitive element 20BK by the rotation of the photosensitive
element 20BK in the B1 direction.
The charged black toner supplied from the developing device 50BK is
attached to the electrostatic latent image formed in this way,
developed into black, and visualized. The toner image as a black
visible image obtained by development is primarily transferred to
the transfer belt 11 moving in the A1 direction by the primary
transfer roller 12BK. Foreign substances such as the toner
remaining after transfer are scraped and removed by the cleaning
device 70BK and stockpiled. The photosensitive element 20BK is then
served for next charging by the charging device 30BK.
Similarly even in the other photosensitive elements 20Y, 20M, and
20C, the toner images of respective colors are formed, and the
toner images of respective colors formed are sequentially primarily
transferred at the same position on the transfer belt 11 moving in
the A1 direction by the primary transfer rollers 12Y, 12M, and
12C.
As the transfer belt 11 rotates in the A1 direction, the toner
images superimposed on the transfer belt 11 move to a transfer
section as a secondary transfer section that is a position facing
the secondary transfer roller 5. A secondary transfer bias of
predetermined amplitude is applied by the high voltage source of
the secondary transfer device 47 under control of the control
section 36, and so the secondary transfer is performed such that
the toner images are transferred onto the transfer sheet S in the
transfer section.
The transfer sheet S transported to between the transfer belt 11
and the secondary transfer roller 5 is one which was delivered from
the sheet feed device 23 and then sent out by the resist roller
pair 13 so as to match timing when the front end of the toner image
on the transfer belt 11 faces the secondary transfer roller 5 based
on a detection signal from a sensor.
The toner images of all colors are collective transferred and
supported to the transfer sheet S and the transfer sheet S is
separated from the transfer belt 11 due to the curvature of the
transfer entrance roller 74, transported in the C1 direction and
enters the fixing device 6. When the transfer sheet S passes
through the fixing nip 80, the supported toner images are fixed to
the transfer sheet S due to influence of heat and pressure, and a
full-color color image as a synthetic color image is formed on the
transfer sheet S by this fixing process.
The transfer sheet S which passed through the fixing device 6 and
completed fixing is stacked on the paper discharge tray 17 through
the discharging roller 7. The transfer belt 11 that finished the
secondary transfer is cleaned by the cleaning device 32 each time
and gets ready for next primary transfer.
In the image forming device 100 described, a failure of the fixing
device 6 is diagnosed through the failure diagnosis device 110 as
will be described later.
A failure of the fixing device 6 diagnosed by the failure diagnosis
device 110 relates to poor oil feeding of the fixing belt 64, that
is, a failure or functional deterioration of the releasing agent
supply unit 90.
A failure or functional deterioration of the releasing agent supply
unit 90 will be described.
As described above, the releasing agent supply unit 90 repetitively
circulates oil to be reused in view of economic and environmental
efficiencies.
Schematically, if the image forming operation is performed and the
paper is passed through the fixing device 6 in the image forming
device 100 as described above, a failure or function deterioration
in the releasing agent supply unit 90 with the above-described
configuration occurs in the following order:
1. the oil filter 88 is gradually polluted by filtration of the
impurities, so that the filtration function deteriorates,
2. as the filtration function of the oil filter 88 deteriorates,
polluted oil is supplied to the coating felt 93,
3. the coating felt 93 is clogged, so that an oil supply amount to
the fixing belt 64 decreases, and
4. as the oil supply amount to the fixing belt 64 decreases, a
separation jam caused by poor separation of the transfer sheet S
from the fixing belt 64 or the pressing roller 63, locking in
meshing between the output gear 86a and the driving gear 75, and
locking of the motor 86 occur.
The failure or the functional deterioration will be described below
in more detail.
In the above-described image forming operation in the image forming
device 100, at the initial stage, clean oil is supplied to the
coating felt 93, the degree of contamination of the oil filter 88
is low even when oil is circulated, and thus good filtration
function, in other words, good filtration ability is obtained.
However, if the image forming number, in other words, a number of
printed sheets increases, the oil filter 88 is polluted due to
filtration of the impurities, and so the filtration function
gradually deteriorates. For this reason, oil supplied, in other
words, input to the coating felt 93 is also gradually polluted by
the impurities, the function of the coating felt 93 deteriorates
due to clogging or the like, and the oil supply amount to the
fixing belt 64 decreases. In this situation, oil is not
sufficiently supplied to the transfer sheet S passing through the
fixing nip 80, and the oil supply function deteriorates. In the
worst case, a separation jam that is poor separation of the
transfer sheet S from the fixing belt 64 or the pressing roller 63,
that is, a so-called fixing jam happens. If such oil supply
function deterioration happens, frictional resistance force between
the oil coating roller 91 and the fixing belt 64 increases. The
frictional resistance force acts as brake force against rotation of
the fixing belt 64, and thus a load of the motor 86 increases. In
the worst case, locking in meshing between the output gear 86a and
the driving gear 75, and locking of the motor 86 happen.
As a technique of dealing with the failure or the functional
deterioration of the releasing agent supply unit 90, a technique of
estimating the degree of contamination of oil and replacing the oil
filter 88 or the coating felt 93 at appropriate timing may be
considered.
However, the degree of contamination of oil depends on a use
environment of the image forming device 100, the fixing device 6,
and the releasing agent supply unit 90 such as a kind of the
transfer sheet S used for image forming, for example, a kind of the
transfer sheet S, depending on which is large or small in paper
powder amount is determined, a toner condition used for image
forming, for example, a toner amount depending on whether an image
forming area ratio is large or smaller. Therefore, it is difficult
to exactly estimate the degree of contamination of oil. For
example, if the degree of contamination of oil is estimated and
replacement timing of the oil filter 88 is determined by assuming
that a kind of the transfer sheet S and the toner amount that cause
the worst oil contamination are used, when the transfer sheet S of
a paper kind that generates a small amount of paper powder is used,
replacement timing of the oil filter 88 is too early, and the oil
filter 88 that can be still used is replaced, leading to waste. If
the degree of contamination of oil is estimated and replacement
timing of the oil filter 88 is determined by assuming a standard
oil contamination condition, that is, a standard use of the image
forming device 100, when the transfer sheet S of a paper kind that
generates a large amount of paper powder is used, replacement
timing of the oil filter 88 is too late, and the oil filter 88 is
replaced after the separation jam happens, leading to downtime.
For this reason, the failure diagnosis device 110 performs failure
diagnosis of the fixing device 6 including estimation of a cause of
trouble of the fixing device 6, that is, a failure or functional
deterioration of the releasing agent supply unit 90, specially,
functional deterioration or degradation of the oil filter 88 and
the coating felt 93. Functional deterioration of the oil filter 88
is equivalent to an increment in the degree of contamination of
oil, and function deterioration of the coating felt 93 is
equivalent to a decrement in an oil attachment amount of the fixing
belt 64. If function deterioration of the oil filter 88 and the
coating felt 93 can be estimated, appropriate replacement timings
of the oil filter 88 and the coating felt 93 can be also
estimated.
FIG. 4 illustrates a current wave of a driving current of the motor
86 when a paper .alpha. and a paper .beta., that is, two kinds of
transfer sheets S pass through the fixing nip 80 at the time of
image forming and a current wave of a driving current of the motor
86 when the transfer sheet S does not pass through the fixing nip
80. In FIG. 4, a time period indicated by A represents when the
transfer sheet S passes through the fixing nip 80, and a time
period indicated by B represents when the transfer sheet S does not
pass through the fixing nip 80. The paper .alpha. and the paper
.beta. are different in thickness, and the paper .alpha. is thicker
than the paper .beta..
It can be understood from FIG. 4 that in both the paper .alpha. and
the paper .beta., a current value of the driving current of the
motor 86 increases when the transfer sheet S passes through the
fixing nip 80. This is because a load of the motor 86 for
transporting the transfer sheet S, that is, a driving load of the
fixing device 6 increases when the transfer sheet S passes through
the fixing nip 80.
The failure diagnosis device 110 performs failure diagnosis of the
fixing device 6 including estimation of a cause of trouble of the
fixing device 6, that is, a failure or function deterioration of
the releasing agent supply unit 90, specially, function
deterioration or degradation of the oil filter 88 and the coating
felt 93 as a plurality of causes of trouble of the fixing device 6
by using the driving load of the fixing device 6, specially, the
current value of the driving current of the motor 86.
To this end, the control section 36, for example, measures the
current value of the driving current of the motor 86 in performing
driving control of the motor 86.
Specifically, the control section 36 measures and acquires the
current value of the driving current of the motor 86 during a time
from the signal reception start time of the fixing entrance sensor
83 to the signal reception start time of the fixing exit sensor 84
as the driving load of the fixing device 6 and stores the current
value in the RAM. In this regard, the control section 36 functions
as a driving load measuring unit, a driving load acquiring unit,
and a driving load recording unit as a first driving load recording
unit. The driving load measuring unit or the driving load acquiring
unit may include the fixing entrance sensor 83 or the fixing exit
sensor 84 in addition to the control section 36.
Further, in the present embodiment, the driving current of the
motor 86 is used as the driving load of the fixing device 6, but if
it is possible to measure any other value representing the driving
load of the fixing device 6, the value may be used in failure
diagnosis of the fixing device 6 including the estimation.
As described above, the control section 36 drives the communication
section 37 and requests the failure diagnosis device 110 to
establish communication for transmitting the paper transport time
stored in the control section 36 as the paper transport time
recording unit while identifying the corresponding image forming
device 100 to the failure diagnosis device 110. At this time, the
control section 36 requests the failure diagnosis device 110 to
establish communication for transmitting, together with the paper
transport time, the driving load stored in the control section 36
as the driving load recording unit while identifying a
corresponding image forming device 100 to the failure diagnosis
device 110.
The failure diagnosis device 110 has the following configuration
for diagnosing a failure of the fixing device 6. The failure
diagnosis device 110 collects a plurality of paper transport times
and a plurality of driving loads, which are acquired by the control
section 36 as the paper transport time acquiring unit and the
driving load acquiring unit and recorded by the control section 36
as the transport time recording unit and the driving load recording
unit, through the communication section 37, the LAN 120, and the
Internet 130. To this end, the failure diagnosis device 110
includes a data collector 111 connected to the Internet 130, a
state database 112 that is a paper transport time recording unit as
a second paper transport time recording unit and a driving load
recording unit as a second driving load recording unit that store
and accumulate the plurality of the paper transport times and the
plurality of the driving loads collected by the data collector 111
in a manner in which they are assigned to the corresponding image
forming devices 100, an inference engine 113 as a diagnosis unit
that diagnoses a failure of the fixing devices 6 of the
corresponding image forming devices 100 using the plurality of the
paper transport times and the plurality of the driving loads of
each image forming devices 100 accumulated in the state database
112, and a system controller 114 that is connected with the PC 140
through the LAN 150 and controls the data collector 111, the state
database 112, and the inference engine 113.
The data collector 111 has a predetermined communication function
that performs communication for collecting the plurality of the
paper transport times and the plurality of the driving loads for
each image forming devices 100. The data collector 111 receives a
communication request from the communication section 37 for
transmitting the plurality of the paper transport times and the
plurality of the driving loads stored in the control section 36 as
the paper transport time recording unit and the driving load
recording unit to the failure diagnosis device 110. When the
request is received, the data collector 111 instructs the
corresponding image forming device 100 to transmit the plurality of
the paper transport times and the plurality of the driving loads
and collectively receives the plurality of the paper transport
times and the plurality of the driving loads from the corresponding
image forming device 100.
The state database 112 has a memory function for storing the
plurality of the paper transport times and the plurality of the
driving loads and is formed by a semiconductor medium (for example,
ROM or non-volatile memory), an optical medium (for example, DVD,
MO, MD, or CD-R), a magnetic medium (for example, hard disk,
magnetic tape, or flexible disk), etc. The state database 112
records, in an additive manner as a new file, the plurality of the
paper transport times and the plurality of the driving loads
received by the data collector 111 in a manner in which they are
assigned to the corresponding image forming device 100.
The inference engine 113 includes a CPU or the like that performs
computation for performing the diagnosis. The inference engine 113
also has a function for notifying that failure occurs in the fixing
device 6 while identifying the image forming device 100 in which
that failure occurs, for example, by transmitting an electronic
mail to a service engineer or a user when the fixing device 6 is
diagnosed as having a failure. This point will be described
later.
The inference engine 113 computes and acquires a plurality of
driving loads per time, that is, in unit time length, i.e., a
plurality of unit time driving loads by dividing, by each of the
plurality of the paper transport times, the corresponding driving
load, they being accumulated in the state database 112. In this
regard, the inference engine 113 functions as the driving load
computing unit that is a unit time driving load computing unit and
the driving load acquiring unit that is a unit time driving load
acquiring unit. The plurality of the driving loads that is the
plurality of the unit time driving loads is stored and accumulated
in the state database 112 in a manner in which they are assigned to
the corresponding image forming devices 100. In this regard, the
state database 112 functions as the driving load recording unit
that is a unit time driving load recording unit.
Further, in the present embodiment, the paper feed tray 15 is
configured to be able to stack the transfer sheets S of multiple
sizes, and the paper transport time is different depending on the
size of the transfer sheet S. Therefore, the inference engine 113
is configured to function as the unit time driving load computing
unit, the driving load computing unit, the unit time driving load
acquiring unit, and the driving load acquiring unit. However, when
the paper feed tray 15 is configured to stack the transfer sheet S
of a single size, the driving load measured and acquired by the
control section 36 that functions as the driving load measuring
unit and the driving load acquiring unit can be used "as is"
instead of the unit time driving load, and it is unnecessary to
compute, acquire, record, transmit, and receive the paper transport
time. Further, even when the paper feed tray 115 is configured to
be able to stack the transfer sheets S of multiple sizes, if the
image forming device 100 has a size detecting unit that detects the
size of the transfer sheet S in the paper feed tray 115, the unit
time driving load and the driving load may be computed and recorded
by dividing the driving load by the size of the transfer sheet S
detected by the size detecting unit. In this case, instead of the
paper transport time, the size of the transfer sheet S is detected,
acquired, recorded, transmitted, and received.
In order to perform such control and store data necessary for
control, the system controller 114 includes a CPU and, as a memory,
a ROM as a first memory unit that stores an operation program of
the failure diagnosis device 110 and a variety of data necessary
for an operation of the operation program and a RAM as a second
memory unit that stores data necessary for an operation of the
failure diagnosis device 110.
The failure diagnosis device 110 performs a failure diagnosis
method for diagnosing a failure of the fixing device 6 in the image
forming device 100 using a state discrimination method which will
be described next.
[Description of the State Discrimination Method]
A failure state is considered to be recognized by a peculiar
unsteady movement in various forms in variation of data with time
that was steady in a normal state.
The failure diagnosis device 110 uses, as target data for failure
state determination, first to third feature quantities computed by
the following method by the inference engine 113.
The first feature quantity represents an average of the plurality
of the unit time driving loads, in a corresponding image forming
device 100, which are acquired by the inference engine 113 as the
driving load acquiring unit and recorded by the state database 112
as the driving load recording unit. The first feature quantity is
computed by the inference engine 113 as an average value of the
plurality of the unit time driving loads. In this regard, the
inference engine 113 functions as a first feature quantity
computing unit that computes the first feature quantity, that is,
an average value computing unit.
The second feature quantity represents a deviation of the plurality
of the unit time driving loads, in a corresponding image forming
device 100, which are acquired by the inference engine 113 as the
driving load acquiring unit and recorded by the state database 112
as the driving load recording unit. The second feature quantity is
computed by the inference engine 113 as a standard deviation of the
plurality of the unit time driving loads. In this regard, the
inference engine 113 functions as a second feature quantity
computing unit that computes the second feature quantity, that is,
a standard deviation computing unit. The second feature quantity
may be a variance of the plurality of the unit time driving loads.
In this case, the inference engine 113 functions as a variance
computing unit.
The third feature quantity represents a maximum value of the
plurality of the unit time driving loads, in a corresponding image
forming device 100, which are acquired by the inference engine 113
as the driving load acquiring unit and recorded by the state
database 112 as the driving load recording unit. The third feature
quantity is computed, specially, selected by the inference engine
113 as a maximum value of the plurality of the unit time driving
loads. In this regard, the inference engine 113 functions as a
third feature quantity computing unit that computes the third
feature quantity, that is, a maximum value computing unit.
When the first to third feature quantities are computed from the
same plurality of the unit time driving loads, a set of three
values composed of the first to third feature quantities configures
a condition data C in the corresponding image forming device 100. A
plurality of condition data C is computed from the different
pluralities of the unit time driving loads mutually and
progressively shifted on time series as will be described later,
and thus condition data sets C1 to Cn in the corresponding image
forming device 100 are configured. The condition data sets C1 to Cn
represent a temporal change in the condition data C in the
corresponding image forming device 100, in other words, a temporal
change in the first to third feature quantities in the
corresponding image forming device 100.
The inference engine 113 as a diagnosis unit diagnoses a failure of
the fixing device 6 disposed in the corresponding image forming
device 100 for each image forming device 100 using the condition
data sets C1 to Cn as follows.
The condition data sets C1 to Cn are created as will be described
later and transmitted to a discriminator configured with the
inference engine 113. The inference engine 113 as the discriminator
computes a preliminary diagnosis result as to whether or not the
fixing device 6 has a failure.
Specially, the inference engine 113 as the discriminator
discriminates whether each feature quantity configuring each
condition data C is normal or abnormal based on the following
Expression (1) and provides a value Outi. The value Outi (here, 1
or -1) given when it is normal is different from the value Quti
given when it is abnormal. In Expression (1), bi and sgni are
determination conditions decided by using a boosting method which
will be described later. The bi is a threshold of each feature
quantity configuring each condition data Ci, and the sgni is a
discrimination sign of each feature quantity configuring each
condition data Ci. That is, the discriminator is created for each
of the condition data sets C1 to Cn that are computation results of
the feature quantity. Outi=1(sgni.times.(Ci-bi).gtoreq.0)
Outi=-1(sgni.times.(Ci-bi)<0) 1
Since the preliminary discrimination is not a decisive factor in
failure diagnosis, the discrimination at this time is referred to
as a weak discrimination process. In this regard, the discriminator
configured with the inference engine 113 forms a weak discriminator
called a stamp weak discriminator. Further, the control section 36
as the diagnosis unit functions as a preliminary diagnosis result
computing unit, that is, a weak discrimination process unit.
The inference engine 113 that functions as the diagnosis unit
configures a discriminator that discriminates whether the fixing
device 6 is in the normal state or in the abnormal state based on
the following Expression (2) using the Outi value.
Specially, the discriminator computes a discrimination index value
F as a vote result value of a weighted majority vote by a weighted
majority vote expressed in Expression (2) and discriminates that it
is in the failure state if the discrimination index value F is
equal to or less than zero (0). In Expression (2), i=1 to n.
Further, in Expression (2), .alpha.i is a values to be multiplied
to the feature quantities configuring each condition data Ci in a
computation method of the weighted majority vote decided by using
the boosting method which will be described later, and the
discrimination index value Fi is computed by a sum of multiplied
values. In this regard, the inference engine 113 as the diagnosis
unit functions as a weighted majority vote computing unit, a
weighted majority vote discriminator, or a discrimination index
value computing unit. Fi=.SIGMA.(.alpha.i.times.Outi) (2)
Further, the stamp discriminator as the weak discriminator has a
merit of being capable of performing a CPU computation at a high
speed, and the sufficient degree of accuracy is obtained in the
present method that uses the weighted majority vote. Therefore, the
stamp discriminator is very desirable to realize a failure state
discrimination technique with high accuracy and at a low cost.
The boosting method will be described. The boosting method is a
supervised learning algorithm and is explained in detail in
Mathematical science, No. 489, March, 2004, titled "Information
geometry of statistical pattern identification". The boosting
method is a well-known method, and thus description thereof is
omitted.
In order to determine bi, sgni, and .alpha.i using the boosting
method, condition data that is already known as corresponding to a
normal state and condition data that is already known as
corresponding to a failure state or a predictive failure state are
first created. To this end, a tester having the same configuration
as the color image forming device illustrated in FIG. 2 was
prepared. Continuous printing of continuously outputting test
images was performed using the print tester, and unit time driving
loads were sequentially recorded. In order to prevent erroneous
detection in which it is determined as the failure state because
the unit time driving loads are different depending on a kind of
the paper (see FIG. 4), the papers of multiple kinds from a thin
paper to a thick paper were used in the experiment.
Trouble or a failure of the fixing device 6 as a target of the
present experiment includes functional deterioration or degradation
of the oil filter 88 that causes a separation jam due to poor
separation of the transfer sheet S from the fixing belt 64 or the
pressing roller 63 and function deterioration or degradation of the
coating felt 93 that causes locking in meshing between the output
gear 86a and the driving gear 75 or locking of the motor 86.
FIG. 5 illustrates time-series data of the unit time driving load
including a first time period in which the separation jam
frequently occurs due to deterioration of the oil filter 88 and a
second time period in which locking frequently occurs due to
deterioration of the coating felt 93. In FIG. 5, a horizontal axis
denotes a fixing number (kp), and a vertical axis denotes a feature
quantities (driving current/time). A vertical axis of a fragmentary
view (a) of FIG. 5 denotes an average value of the unit time
driving loads as the first feature quantity, a vertical axis of a
fragmentary view (b) of FIG. 5 denotes a standard deviation of the
unit time driving loads as the second feature quantity, and a
vertical axis of a fragmentary view (c) of FIG. 5 denotes a maximum
value of the unit time driving loads as the third feature quantity.
The feature quantities are computed and plotted as follows. For
example, the average value, the standard deviation, and the maximum
value are computed using the unit time driving loads respectively
applied in fixing processes of 1 to 10 kp, and the computed values
are plotted on a portion of 1 kp. Next, the average value, the
standard deviation, and the maximum value are computed using the
unit time driving loads respectively applied in fixing processes of
2 to 11 kp, and the computed values are plotted on a portion of 2
kp. Finally, the average value, the standard deviation, and the
maximum value are computed using the unit time driving loads
respectively applied in fixing processes of 2000 to 2009 kp, and
the computed values are plotted on a portion of 2000 kp.
In all of the fragmentary views (a) to (c) of FIG. 5, an area
representing an abruptly increased value near 172 kp corresponds to
the first time period, and an area representing an abruptly
increased value near 200 kp corresponds to the second time period.
When the fixing device 6 was observed in the first period, clogging
of the oil filter 88 occurred, and the transfer sheet S was wound
around the fixing belt 64, frequently causing the separation jam.
Further, the coating felt 93 started to be polluted, and the oil
supply amount to the fixing belt 64 was scant. When the fixing
device 6 was observed in the second period, clogging occurred in
the coating felt 93 as well as the oil filter 88, and so the oil
supply amount to the fixing belt 64 was much decreased. Thereby,
the frictional resistance force between the oil coating roller 91
and the fixing belt 64 increased, so that the motor 86 was in a
state in which locking was likely to occur. Accordingly, it can be
understood that the first to third feature quantities near 172 kp
are suitable to be used for diagnosing a failure of the fixing
device 6 caused by deterioration resulting from clogging of the oil
filter 88, and the first to third feature quantities near 200 kp
are suitable to be used for diagnosing a failure of the fixing
device 6 caused by deterioration resulting from clogging of the
coating felt 93.
Further, even though the papers of multiple different kinds were
used in the initial period, the middle period, and the terminal
period of the experiment, in all of F the fragmentary views (a) to
(c) of FIG. 5, a feature quantity change did not appear. Therefore,
it is understood that it is possible to prevent failure
discrimination from being erroneously performed due to a change in
a kind of the paper by virtue of using the first to third feature
quantities.
In order to apply the condition data including the feature
quantities computed by the above-described method to learning by
the boosting method, that is, to creating bi, sgni, and .alpha.i
and to a test of the booting method, that is, confirming the
effects of bi, sgni, and .alpha.i created, the condition data was
randomly sorted into a learning condition data and a test condition
data such that each of the both includes the condition data
corresponding to failure periods corresponding to the first and
second time periods, and feature quantity changes, that is,
condition data sets created in this way were used as a set of the
learning condition data and a set of the test condition data set,
respectively.
Subsequently, in performing leaning by the boosting method, changes
of the feature quantities in the learning condition data set was
illustrated by a graph having a print number integration value as a
horizontal axis. An abnormal period was visually estimated, and a
label, that is, Outi corresponding to a period estimated as
abnormal in the learning condition data set is given -1 (a failure
period), and the other labels, that is, Outi is given 1 (a normal
period). Learning by the boosting method was repetitively performed
hundred times to decide b1 to b100, sgn1 to sgn100, and .alpha.1 to
.alpha.100. Further, in order to repetitively perform learning by
the boosting method hundred times, 100 condition data sets were
used for learning.
A result of computing an F value using data used for learning is
illustrated in FIG. 6. It was confirmed that, regarding the
supervised data to which the labels are attached, learning was
appropriately performed, and as a result, a discriminator using the
weak discriminators and the weight majority vote, in which only
failure periods respectively corresponding to the first and second
time periods became minus in the F value, was generated. Next, as a
result of verifying, using the test condition data set, the degree
of accuracy of the discriminator using the weak discriminators and
the weight majority vote, the result was the same as that
illustrated in FIG. 6. Similarly to the learning condition data
set, 100 condition data sets were used in the test. An output F
value of the discriminator that performs a computation using b,
sgn, and .alpha. which were previously decided became minus in
periods corresponding to the first and second time periods, and
thus it was confirmed that a failure was diagnosed with the
excellent degree of accuracy.
As described above, in the failure diagnosis device 110, the
inference engine 113 functions as the discriminator using bi, sgni,
and .alpha.i previously created as described above, and the failure
diagnosis device 110 functions as the above-described other units.
Therefore, when the image forming operation is repetitively
performed, based on a change of the F value to a minus value, it is
possible to estimate or identify a failure of the fixing device 6,
particularly, causes of a failure of the fixing device 6 including
deterioration of the oil filter 88 and deterioration of the coating
felt 93 or to perform failure diagnosis and detection of the fixing
device 6 including identification by the estimation.
Generally, a cause of a problem, trouble, or a failure related to
the fixing device is various. For this reason, estimating a failure
cause is very effective in reducing a time taken for performing
repair or maintenance or preventing an unnecessary repair from
being performed in a portion other than a failure cause. An
application of the invention is very effective because downtime
caused by repair is reduced by estimating a cause of a failure of
the fixing device 6.
In the present embodiment, estimating a cause of trouble of the
fixing device 6 is explained in connection with deterioration of
the oil filter 88 and deterioration of the coating felt 93.
However, since a cause of a problem or a failure related to the
fixing device is various as described above, if the failure
diagnosis device 110 is configured to let the inference engine 113
to function as the discriminator using bi, sgni, and .alpha.i
created as described above and to function as the above-described
other units, for further kinds of failure causes, it is possible to
perform failure diagnosis including estimation of further kinds of
failure causes of the fixing device 6. In this case, it is very
effective in preventing an unnecessary repair from being performed
in a portion other than a failure cause, and it is more effective
in reducing downtime by repair.
Further, by adjusting the values of bi, sgni, and .alpha.i created
as described above, it is possible to perform failure diagnosis
including anticipation or prediction of a failure that will occur
soon, that is, a sign of a failure as well as diagnosis of a
failure that actually occurred. In this case, in the failure
diagnosis device 110, the values of bi, sgni, and .alpha.i are set
in that manner.
As described above shortly, when the fixing device 6 is diagnosed
as having a failure, the inference engine 113 notifies the service
engineer or the user of that effect via an electronic mail while
identifying the image forming device 100 having the failure. In
this regard, the inference engine 113 functions as an alarm
transmitting unit. Specially, when the F value computed by the
inference engine 113 that functions as the above-described units
became minus in periods corresponding to the first time period and
the second time period and so the fixing device 6 is diagnosed as
having a failure, as illustrated in FIG. 6, the inference engine
113 that functions as the alarm transmitting unit may activate an
alarm, in addition to by notifying that the fixing device 6 has the
failure while identifying the image forming device 100, by
notifying that the oil filter 88 of the fixing device 6 gets
deteriorated in the case of corresponding to the first time period,
and that the coating felt 93 gets deteriorated in the case of
corresponding to the second time period, or alternatively or
additionally notifying that it is inferred that a failure or a
breakage will occur soon. As a result, downtime taken for
maintenance is reduced. A terminal such as a PC that receives an
electronic mail or the like, and notifies and informs the service
engineer of that effect functions as an informing unit.
In this way, when alarm activation is performed in several stages,
it encourages failure restoration of the fixing device 6 to be
performed in several stages. In order to discriminate which of the
first time period and the second time period is a period in which
the F value became minus, a method of discriminating based on
whether a fixing number is near 127 kp or near 200 kp may be used.
Alternatively, a plurality of threshold values may be used for the
F value. For example, a threshold A and a threshold B (A>B) may
be used. When the F value is less than only the threshold A, it is
determined that the period corresponds to the first time period
and, for example, it is recognized as an initial period failure
state. In this case, replacement of the oil filter 88 is
encouraged. On the other hand, when the F value is also less than
the threshold B, it is determined that the period corresponds to
the second time period and, for example, it is recognized as a
terminal period failure state. In this case, replacement of the
coating felt 93 is encouraged. When it is recognized as the initial
period failure state, even after that, the fixing device 6 can be
continuously used by replacing the oil filter 88. When it is
recognized as the terminal period failure state, since it means
that the oil supply amount is not improved by replacing only the
oil filter 88, the fixing device 6 may be encouraged to be replaced
without encouraging the replacement of the coating felt 93.
Alternatively, replacement of the coating felt 93 may be
encouraged. In this case, even after that, the fixing device 6 may
be continuously used. When alarm activation is performed in several
stages, it is possible to remarkably improve economic and
environmental merits and reduce downtime. However, "the terminal
period failure state", alarm activation may be performed once at a
time corresponding to "the terminal period failure state" to
encourage replacement of the oil filter 88 and the coating felt 93.
Even in this case, the fixing device 6 is allowed to be
continuously used. Even when alarm activation is performed once,
replacement of the fixing device 6 may be encouraged.
Further, the function as the alarm transmitting unit may be given
to another part of the failure diagnosis device 110 other than the
inference engine 113, for example, the data collector 111 having
the communication function. A notification of that effect to the
user may be displayed and informed on the LCD device 43 of the
corresponding image forming device 100 by the inference engine 113
or the data collector 111 as the alarm transmitting unit via the
Internet 130. When the corresponding image forming device 100 has
an alarm notification device or the like that generates a sound
such as a voice, the alarm notification device may be used to
inform that effect in a similar manner, and the above-described
methods may be appropriately combined. In the case where the image
forming device 100 performs such informing, the LCD device 43 or
the like functions as the informing unit.
Execution of the operation, the function, or the failure diagnosis
method of the failure diagnosis device 110 as described above may
be realized by executing a failure diagnosis program that is, a
program for performing the failure diagnosis method stored in the
memory of the system controller 114. In this regard, the system
controller 114 functions as a failure diagnosis program storage
unit.
The failure diagnosis program and a computer-usable medium for
recording the failure diagnosis program are described here. The
program is stored in the memory of the system controller 114 and
executed by the CPU of the system controller 114 or the CPU of the
inference engine 113. The memory corresponds to the computer-usable
medium. The computer-usable medium for recording the program may
include any of a semiconductor medium (for example, ROM or
non-volatile memory), an optical medium (for example, DVD, MO, MD,
or CD-R), or a magnetic medium (for example, hard disk, magnetic
tape, or flexible disk). The recording medium also includes a
storage device such as a hard disk of a sever computer in an
external information input device that stores the program when the
program is downloaded and distributed through a user computer or
the like connected to a network such as the Internet or the LAN. An
execution aspect of the program includes a case in which part or
all of actual processing is performed by an operating system or the
like based on an instruction of the loaded program and the
above-described method is execute by the processing.
In this regard, a recording medium such as a semiconductor medium
in the PC 140 corresponds to a computer-usable medium. An operator
who operates the PC 140 can perform update, maintenance or the like
of the failure diagnosis device 110, for example, by appropriately
browsing the driving load stored in the state database 112 and
newly generating, correcting, and deleting the inference engine 113
on the corresponding image forming device 100.
The failure diagnosis device 110 is connected to a plurality of
image forming devices 100 to be able to perform failure diagnosis
for each of the image forming devices 100 as described above.
Therefore, it is possible to surely improve a data generation
method including a computation method of each feature quantity
described above or discrimination constants such as bi, sgni, and
.alpha.i, which are used in performing failure diagnosis, in an
integrated manner. As a result, it is possible to easily and
securely improve the quality of failure diagnosis. Further, since
the boosting method having a relatively small number of steps is
used as described above, even though an amount of data related to
the driving load or the like accumulated in the state database 112
becomes huge, it is possible to timely perform diagnosis at a high
speed.
Since failure diagnosis is performed by processing having a
relative small number of steps, the function of the failure
diagnosis device 110 may be implemented in the image forming device
100 described above, for example, in the control section 36. In
this case, the image forming device 100 configures the failure
diagnosis system 1. A configuration example in which the control
section 36 in the image forming device 100 has the same function as
the failure diagnosis device 110 is illustrated in FIG. 7. In the
configuration example, as illustrated in FIG. 7, the control
section 36 has the respective units and functions of the respective
discriminators disposed in the failure diagnosis device 110,
particularly, in the inference engine 113 such as the diagnosis
unit, the failure diagnosis program storage unit, and the alarm
transmitting unit. Further, the control section 36 as the failure
diagnosis device further includes functions as the paper transport
time computing unit, the paper transport time acquiring unit, the
paper transport time recording unit, the driving load measuring
unit, the driving load acquiring unit, the driving load recording
unit, the unit time driving load computing unit, and the unit time
driving load recording unit. Further, in order to execute the
failure diagnosis method or the failure diagnosis program, the
paper transport time computing unit, the paper transport time
acquiring unit, the paper transport time recording unit, the
driving load acquiring unit, the driving load recording unit, the
unit time driving load computing unit, and the unit time driving
load recording unit are used.
Further, in the configuration example, when the fixing device 6 is
diagnosed as having a failure, the LCD device 43 functions as the
informing unit for displaying and informing that effect to the
user. Specially, when the F value computed by the control section
36 that functions as the failure diagnosis device became minus in
periods corresponding to the first time period and the second time
period and so the fixing device 6 is diagnosed as having a failure,
as illustrated in FIG. 6, the LCD device 43 that functions as the
informing unit activates an alarm under control of the control
section 36 by notifying, in addition to that the fixing device 6
has the failure, that the oil filter 88 of the fixing device 6 gets
deteriorated in the case of corresponding to the first time period,
and that the coating felt 93 gets deteriorated in the case of
corresponding to the second time period, or alternatively or
additionally displaying that it is inferred that such a failure or
a breakage will occur soon. Thereby, downtime taken for repair or
maintenance is reduced as described above. The informing unit is
not limited to the LCD device 43. When the alarm notification
device that generates a sound such as a voice is disposed in the
image forming device 100, the alarm notification device may be used
to inform that effect. When the image forming device 100 has the
communication function such as the LAN 120 and the Internet 130,
the communication function may be used to transmit an electronic
mail or the like to the service engineer or the user. The
above-described methods may be appropriately combined.
The exemplary embodiments of the invention have been described, but
the invention is not limited to the specific embodiments. Various
modification and changes can be made to the invention within the
technical spirit of the invention as set forth in claims unless
specially limited in the above description.
For example, as the feature quantity used for failure diagnosis, in
the above-described embodiment, the first to third feature
quantities are used, since higher degree of diagnosis accuracy is
obtained than the first and second quantities are used. However, as
the feature quantity used for failure diagnosis, only the first and
second feature quantities may be used, and another value such as a
statistical value may be used as the third feature quantity.
Further, in addition to the first to third feature quantities,
another value such as statistical value may be used.
In the configuration example illustrated in FIG. 1, the paper
transport time acquired by the paper transport time acquiring unit
and the driving load acquired by the driving load acquiring unit
may be transmitted to the failure diagnosis device to compute and
record the unit time driving load in real time. In this case, the
paper transport time recording unit and the driving load recording
unit at the image forming device side may be omitted.
The releasing agent supply unit may be disposed at the fixing unit
side as in the above-described embodiment or may be disposed on the
main body side of the image forming device instead of the fixing
unit side. Selecting one from these configurations may be performed
depending on an arrangement position of a constitution of
eliminating an estimated cause of a failure and convenience of its
replacement, repair, and other maintenances.
The fixing device may be another fixing device employing another
method such as a roller fixing system other than a fixing device
employing a belt s system as in the fixing device 6.
The invention may be similarly applied to an image forming device
of a so-called one drum system that obtains a color image by
sequentially forming toner images of respective colors on one
photosensitive element and sequentially superimposing the toner
images of respective colors, instead of the image forming device of
a so-called tandem method but.
The image forming device may be not a complex machine of a copy
machine, a printer, and a facsimile but a single body thereof.
Further, the image forming device may be a complex machine of
another combination such as a complex machine of a copy machine and
a printer.
A direct transfer system in which toner images of respective colors
are directly transferred on a transfer material without using an
intermediate transfer body may be employed in any type of an image
forming device. In this case, toner images on a plurality of image
carriers are directly transferred onto a sheet.
The effects described in the embodiments of the invention are
merely enumeration of most desirable effects achieved by the
invention. The effects of the invention are not limited to those
described in the embodiments of the invention.
According to the invention, since failure diagnosis performed using
the driving load of the fixing section includes estimation of a
cause of a failure, it is possible to make repair or maintenance
easy when failure diagnosis is performed. Further, the failure
diagnosis device of high reliability in which downtime can be
reduced can be provided.
According to the invention, the third feature quantity as well as
the first feature quantity and the second feature quantity may be
used in failure diagnosis performed using the driving load of the
fixing section, and thereby the degree of accuracy of failure
diagnosis is further improved. Therefore, it is possible to make
repair or maintenance further easier when failure diagnosis is
performed. Further, the failure diagnosis device of high
reliability in which downtime can be further reduced can be
provided.
According to the invention, failure diagnosis performed using the
driving load of the fixing section may include estimation of a
plurality of causes of the failure, and when diagnosing the failure
due to one of the causes, perform an output for informing the
failure and the one of the causes. In this case, it is possible to
make repair or maintenance very easy when failure diagnosis is
performed. Further, the failure diagnosis device of extremely high
reliability in which downtime can be largely reduced can be
provided.
According to the invention, failure diagnosis performed using the
driving load of the fixing section may include estimation of the
occurrence of poor feeding of the releasing agent to the fixing
member that is a cause of the failure. In this case, since it is
possible to recognize that poor feeding of the releasing agent to
the fixing member occurred, repair can be performed at a pinpoint
without replacing the whole fixing section. Therefore, it is
possible to make repair or maintenance easier when failure
diagnosis is performed. Further, the failure diagnosis device of
high reliability in which downtime can be reduced can be
provided.
According to the invention, failure diagnosis performed using the
driving load of the fixing section may include estimation of the
occurrence of poor feeding of the releasing agent to the fixing
member resulting from deterioration of the supply member that is a
cause of the failure. In this case, since it is possible to
recognize that poor feeding of the releasing agent to the fixing
member occurred due to deterioration of the supply member, repair
can be performed at a pinpoint by replacing the supply member
without replacing the whole fixing section. Therefore, it is
possible to make repair or maintenance easier when failure
diagnosis is performed. Further, the failure diagnosis device of
high reliability in which downtime can be reduced can be
provided.
According to the invention, failure diagnosis performed using the
driving load of the fixing section may include estimation of the
occurrence of poor feeding of the releasing agent to the fixing
member resulting from deterioration of the filtration member that
is a cause of the failure. In this case, since it is possible to
recognize that poor feeding of the releasing agent to the fixing
member occurred due to deterioration of the filtration member,
repair can be performed at a pinpoint by replacing the filtration
member without replacing the whole fixing section. Therefore, it is
possible to make repair or maintenance easier when failure
diagnosis is performed. Further, the failure diagnosis device of
high reliability in which downtime can be reduced can be
provided.
According to the invention, failure diagnosis may be performed
using the driving current of the fixing section as the driving load
of the fixing section. In this case, it is relatively easy to
acquire the driving load of the fixing section.
Although the invention has been described with respect to specific
embodiments for a complete and clear disclosure, the appended
claims are not to be thus limited but are to be construed as
embodying all modifications and alternative constructions that may
occur to one skilled in the art that fairly fall within the basic
teaching herein set forth.
* * * * *